The present invention relates generally to hand tools using blades, and more specifically to wallboard taping knives and similar tools.
A wallboard taping knife or scraper typically has a large blade with an elongate working edge attached to a handle. As is well known in the art, such tools are used for spreading joint compound over wallboard tape to finish joints of adjacent wallboard panels. Users typically repeatedly dip the knife blade into a container of wallboard joint compound known as a mud pan, and also scrape excess compound from the blade against an edge of the mud pan. Due to the operator stresses on the blade from these various repetitive activities, it is preferred to have the blade well secured to the handle such that there is no play or independent relative movement between the blade and handle. A strong connection between the blade and handle increases operational life of the tool and reduces user fatigue. Thus, one design criteria of such a tool is to reduce independent movement of the blade relative to the handle. Conventional drywall tools address this concern by manufacturing the tool such that the blade is permanently attached to the handle of the tool.
A significant portion of operational wear on taping knives is incurred on the blade edge or at the point where the blade meets the handle. As the blade becomes worn, it becomes more difficult to evenly apply the compound. Since conventional tools have blades that are permanently attached to the tool, when the blade becomes worn, the entire tool must be replaced. Another design criteria of taping knives is maintaining user comfort during periods of extended use.
Utility knives and other tools with replaceable blades are known in the art. However, in such tools removing the blade involves unscrewing and/or opening the tool housing, resulting in a complicated and time-consuming process.